Power electronics circuits, such as DC/DC or AC/DC voltage converters, generally comprise magnetic components—coils and capacitors. By way of example, FIG. 1 shows the circuit diagram of a DC/DC converter CCC comprising a half-bridge inverter O, a full-bridge active rectifier R, a transformer T whose primary winding is linked to the inverter O and whose secondary winding is linked to the rectifier R, and a coil B that is connected in series with said secondary winding but magnetically decoupled from said transformer. These magnetic components (T, B)—and more specifically their magnetic (actually, ferromagnetic) cores—greatly contribute to the bulk of the circuit. Yet, bulk constitutes a major constraint, in particular in onboard—and more specifically aeronautical—applications where the available space is very limited.
It is known practice to implement power electronics circuits in the form of electronic boards comprising a planar printed circuit board substrate bearing surface-mount electrical and electronic components. In these electronic boards, the magnetic components are implemented using planar technology: the windings are formed by the deposition of tracks on one or both sides of the printed circuit board substrate and each magnetic core is composed of a first “E-shaped” (with three legs) or “U-shaped” (with two legs) element, and of a second “I-shaped” (without legs, i.e. plate- or strip-shaped) element closing the magnetic circuit. The first elements are arranged on a first side, called the front side, of the substrate; the second elements are arranged on a second side, called the back side, of the substrate; and the legs pass through the substrate by virtue of through-holes made in the latter. This technique allows the bulk of the magnetic components to be kept down; nevertheless, the thickness of the cores remains relatively significant. Specifically, magnetic circuit theory indicates that the magnetic flux inside a core is inversely proportional to its reluctance, which is itself inversely proportional to its cross section, and hence to its thickness. The requirement to ensure a determined magnetic flux, for a given magnetomotive force, therefore imposes a minimum thickness for the elements forming the magnetic cores.